Genotypic characteristics of ALPS-FAS and ALPS-sFAS patients. The structure of the TNFRSF6 gene showing ALPS-FAS–associated mutations in exons 1-6 (A) encoding the extracellular domain (ECD) and transmembrane domain (TMD) and exons 7-9 (B) encoding the intracellular domain (ICD). Mutations are numbered with respect to the immature protein. The symbols denote missense (●) and frameshift mutations (); deletions and nonsense mutations are also indicated. Mutations denoted with an asterisk are novel. The numbers of unrelated index cases carrying the same mutation are given in brackets. Mutations associated with ALPS-sFAS are shown in panel C.